PARATHYROID DETECTION IN SECONDARY HYPERPARATHYROIDISM WITH I-123 TC-99M-SESTAMIBI SUBTRACTION SINGLE-PHOTON EMISSION COMPUTED-TOMOGRAPHY/

I-123/Tc-99m-sestamibi subtraction single photon emission computed tom ography (SPECT) has been proposed to detect hyperplastic parathyroid t issue, but the clinical usefulness of this technique in secondary hype rparathyroidism is uncertain. The purpose of this study was to evaluat e preoperative parathyroid localization using I-123/Tc-99m-sestamibi s ubtraction SPECT in patients with renal failure and secondary hyperpar athyroidism. Nineteen patients with chronic renal failure and secondar y hyperparathyroidism underwent I-123/Tc-99m-sestamibi subtraction SPE CT imaging preoperatively. None of these patients had undergone previo us neck surgery. The location, weight, and histopathological results o f all identified parathyroid glands were recorded. Surgery was conside red successful in all patients, with resection of a total of 74 hyperp lastic parathyroid glands. I-123/Tc-99m-sestamibi subtraction SPECT co rrectly identified 57 of these parathyroid glands (77% sensitivity). T he mean weight among the true positive glands (n = 57) was 1031 mg (ra nge, 45-7900 mg), and that among the false negative glands (n = 17) wa s 465 mg (range, 20-1800 mg). This difference between the mean weights was statistically significant (P = 0.018). There was a positive corre lation between parathyroid weight and detectability with I-123/Tc-99m- sestamibi subtraction SPECT (Spearman correlation = 0.28; P = 0.0167). I-123/Tc-99m-sestamibi subtraction SPECT is able to correctly localiz e hyperplastic parathyroid glands in patients with renal failure and s econdary hyperparathyroidism, but there is a fairly weak relationship between preoperative detection rate and anatomical parathyroid gland s ize.